Soil Erosion Risk and Flood Behaviour Assessment of Sukhnag catchment, Kashmir Basin: Using GIS and Remote Sensing

Abstract

Kashmir Basin is surrounded on all sides by lofty mountains, there is only one outlet i.e., Jhelum River to drain water from the basin. The mountainous areas of Kashmir Basin have rugged topography and unstable slopes with highly shuttered rocks. Based on these factors, the evaluation of basin characteristics from the morphometric analysis and other associated factors will help to understand the physical behaviour of the area with respect to floods and soil erosion risk. Remote sensing and GIS techniques were applied to extract drainage network using Digital Elevation Model (DEM) to evaluate morphometric parameters for Sukhnag catchment. Lineament, slope and aspect maps were generated to support morphometric parameters to demarcate the soil erosion and flood prone areas during harsh weather conditions. In low lying areas with more habitation and construction on the river banks and flood plains have squeezed the rivers and minimized their water carrying capacity. Morphometry together with lineament density, slope distribution and flood plain conditions helps to classify the catchment into three categories, high, medium and low priority for conservation and management with respect to soil erosion and floods. Among 14 sub-watersheds SF1, 2, 5, 6 and 7 are more prone to landslides and SF10, 12, 13 and 14 are more prone to flood and siltation hazard. More chances of erosion risk in SF1, 2, 5, 6 and 7 can be due to lose upper layer, high altitude, unstable slope and high structural density. Conversely, the floods and siltation hazard are more in low lying subwatersheds as faced in Kashmir Valley (Sept. 2014 Flood). The present work emphasized that categorization of smaller hydrological unit’s i.e., sub-watersheds are ideally recommended for initiating soil conservation and flood mitigation measures in the area.